Has anyone noticed significant throat erosion from extended use of the TSX bullet? As I understand it, the TSX is supposed to be a bit undersized, which as a general principle would tend to lead to more throat erosion. I just wonder if anyone has shot enough of them to actually seen it yet.

i haven't seen anything like it yet, but an old report used to claim boattails gave more erosion than flat base, i suppose the idea is about the same

My Whelen's TSX bullets mic .358" exactly. That's not undersized. And they're flat base not boat tailed. However I doubt I will ever shoot enough to cause erosion of the throat. So basically my answer is, I don't know.

One of the theories is that erosion is caused by "blow-by" as the bullets engrave. Since these bullets engrave easier, the argument can be made they cause LESS erosion. FWIW, Dutch.

quote:

Originally posted by 500grains:
Has anyone noticed significant throat erosion from extended use of the TSX bullet? As I understand it, the TSX is supposed to be a bit undersized, which as a general principle would tend to lead to more throat erosion. I just wonder if anyone has shot enough of them to actually seen it yet.

I just went to my bench to measure what I have laying around..My (Mitutoyo) micrometer reads:

TSX 200 gr. FB .3080
TSX 180 gr. BT .3080
TSX 168 gr. BT .3080
Hot-Cor 165 gr. BT .3080
Hornady 165 gr. IB .3080

What is your source for this info?
On the surface, it couldn't appear to be more bogus.

Throat erosion is caused by hot gasse, produced as the powder burns, these gasses are above the melting point of steel. It has almost nothing to do with the bullet.

I have seen M60 maching gun blank firing barrels burn out as fast, if not faster than the real barrels.

The amount of powder burnt in relation to the volume of the bore is the most significant factor in throat erosion, eg; a 300 win mag will erode throats much faster than a 308 win, same bore volume, but the 300 win burns more powder.

quote:

The amount of powder burnt in relation to the volume of the bore is the most significant factor in throat erosion

Agreed

Warrior

Rancho,

It was through the grapevine that I heard they were undersized. I have not undertaken to measure a bunch of them to find out. Seemed more efficient (i.e., less expensive) to ask people who use them about their experience.

500grains,

I sure don't have any experience as I've yet to fire one. But I do have a box of TSX and BBS and as best as I can tell with calipers they measure the same as HRN 300, 270, and 220, .3750". My calipers do seem quite accurate, I've checked the diameter of several different sizes of cast bullets and caliper results matched the manufacturer's claimed diameter.

Thanks for stating that you have crimped GSC bullets. I will be getting some of those and it's nice to know that a crimp apparently is not a detriment. I consider crimping a requirement of .375 ammo that will be used in the field.

Try slugging the bore of any rifle. You will find the vast majority are a bit oversize. The exceptions I have seen are quality match barrels.

Using my 0-1" micrometer I got the following readings when I measured 5 of each bullet:

Hornady 300g FMJ Encapsulated Solid - 0.375"

Barnes 300g Banded Solid - 0.3745" base and driving bands

Barnes 300g TSX - base diameter 0.375" driving bands 0.3745"

Nosler 265g Partitions - 0.374" (I didn't believe this and measured 10 of these to be sure)

Thanks Mr. Frank,

I wonder if Noslers are suppose to obturate, or get "bumped up"?

I think they call it bore ratio. Relationship of the volume of powder contained in the cartridge body as it relates to the bore diameter, through which the heat and gas must funnel.

P.O. Ackley was always interested in the issue of bore ratio....and relative efficiency.

Paul

500grains,
I noticed in my Remington Sendero .270 Win a throat erosion (non stainless barrel)of about .004" every 260 rounds. I shot a lot of 'old' Barnes X 130grainers and Sierra Game Kings as well. Did not make any difference.
Nice day,
Jan.

Here's a reference:

http://www.gsgroup.co.za/faqbarrelwear.html

The Barnes tsx 570 gr bullet for the 500 nitro is the only one I know of that is undersized .509 instead of .510. I imagine this is to keep this very long bullet from running into problems with all of the different chambers out there and to keep the pressures down in expensive doubles. I have a box and they measure .509 just like it says on the box. Just got done tungsten coating them. This has almost eliminated copper fouling in my highly over bore 30 cal warbird shooting 168gr tsx's at 3650fps and should work good for these bullets in the 500 jeffery I am building. We will see. The warbird has a 28" graphite wrapped ss krieger double cryoed barrel and has over 1000 full power loads with 180 gr tungsten coated partitions at 3525fps and the for mentioned tsx's it's still a 3/8" rifle. These loads burn 102.5-106gr of RL25. Far worse candidate to erode a throat than a more efficient big bore. unless your out shooting Pdogs with your big bore I see nothing to worry about with the tsx's.